Sulfur-resistant ultralow-temperature manganese-based denitration catalyst as well as preparation method and application thereof

Abstract

The invention provides a sulfur-resistant ultralow-temperature manganese-based denitration catalyst as well as a preparation method and application thereof, and belongs to the technical field of catalysts and environmental protection. According to the preparation method of the catalyst, an acidic organic ligand form is adopted, so that the acid site on the surface of the catalyst is improved, and adsorption and reaction of reactant molecules are facilitated; after a catalyst precursor is subjected to low-temperature calcination, a substrate with a rich pore structure is formed in the interior in a strong acid etching manner, and the substrate has a relatively large specific surface area and a relatively large pore structure; precipitation, impregnation and step-by-step calcination are adopted, an organic solvent, a dispersing agent and first ultrasonic treatment are combined in the precipitation process, intermittent ultrasonic treatment is adopted in the impregnation process, and active elements are evenly impregnated inside and outside a catalyst auxiliary agent. The sulfur-resistant ultralow-temperature manganese-based denitration catalyst prepared by the preparation method disclosed by the invention is rich in pore channels and relatively large in specific surface area, active substances and auxiliary elements are uniformly dispersed, and the catalyst has excellent ultralow-temperature catalytic activity and sulfur resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of catalysts and environmental protection, and in particular to a sulfur-resistant ultra-low temperature manganese-based denitration catalyst and a preparation method and application thereof. Background Art

[0002] In recent years, low-temperature denitrification catalysts have become a research hotspot. However, the operating temperature window of most low-temperature denitrification catalysts is above 180°C, and the temperature of the exhaust gas containing nitrogen oxides drops significantly after dust removal and desulfurization treatment, mostly around 150°C or even lower. In order to match the working temperature of the catalyst, it is often necessary to install additional exhaust gas preheating / heat exchange devices, which invisibly increases the operating cost of denitrification. In addition, in non-electric industries such as steel, cement, garbage incineration, biomass incineration, hazardous waste incineration, catalytic cracking, glass, ceramics and other production processes, the flue gas temperature is generally below 300°C, or even below 150°C. Ultra-low temperature denitrification catalysts (operating temperature ≤150°C) can not only reduce energy consumption and save costs, but also expand application scenarios, becoming a research and development hotspot.

[0003] Some ultra-low temperature denitration catalysts in the prior art are manganese-based denitration catalysts, which rely on honeycomb ceramics, TiO2, SiO2, etc. as carriers, and then are mixed with active ingredients for sintering or coating. However, their denitration efficiency at 140°C and 150°C is basically less than 90%, and the anti-sulfur effect is not explicitly mentioned. For example, CN103240081B discloses a manganese-based denitration catalyst (Mn: (Ti+Si) = 0.8: 1) with TiO2-SiO2 as a composite carrier, and the denitration rate at 150°C is 87.8%; CN114904565B discloses a manganese-based denitration catalyst, which includes a honeycomb ceramic carrier and an active coating and a modified coating sequentially coated on the carrier. At 140°C, the denitration efficiency of the catalyst is mostly less than 90%.

[0004] It is worth noting that the residual SO2 in the flue gas will gradually cause irreversible deactivation of the catalyst, which will bring many challenges and difficulties to the industrial application of the catalyst. For example, physical poisoning caused by ammonium sulfate / ammonium bisulfate deposition and chemical poisoning caused by sulfation of active sites will affect the working life and application cost of the catalyst. Therefore, it is urgent to develop a denitrification catalyst with good sulfur resistance and excellent ultra-low temperature denitrification performance.

[0005] At present, many sulfur-resistant denitrification catalysts use TiO2, molecular sieves, activated carbon and other materials as carriers, and adjust the catalyst composition to improve the sulfur resistance. However, such catalysts generally contain more rare earth elements (such as Ce), which may significantly increase the production cost. For example, in CN118491534B, modified activated carbon is used as a carrier and manganese-iron-cerium composite oxide is used as an active component. The co-loading of Mn / Fe / Ce can improve the low-temperature activity and sulfur resistance of the catalyst. The mass percentages of MnO2, Fe2O3 and CeO2 in the total mass of the catalyst are 6.3%, 1.5% and 1.0% respectively; the porous Ti-Si shell of the catalyst prepared in CN116809057B has certain water and sulfur resistance. Based on the mass of TiO2 in the catalyst, the Mn loading amount is 10wt%, the Ce loading amount is 20wt%, and the molar ratio of Si:Ti is 15:100; in CN115869962B, mesoporous TiO2 nanoparticles are prepared by a hydrothermal method as a carrier, and the active components and active additives are loaded by a quantitative impregnation method, which can reduce the SO2 oxidation rate, reduce the generation of metal sulfates and (NH4)HSO4, improve sulfur resistance, and obtain the high-activity anti-sulfur poisoning low-temperature denitrification catalyst.

[0006] In view of this, there is an urgent need to develop a denitrification catalyst that can simultaneously achieve good sulfur resistance, excellent ultra-low temperature denitrification performance, economical and reasonable cost, and certain mechanical strength to avoid breakage and collapse caused by insufficient mechanical strength and reduced catalyst life, so as to meet the needs of the market and industrialization. Summary of the invention

[0007] In view of the deficiencies in the prior art, the present invention discloses a sulfur-resistant ultra-low temperature manganese-based denitration catalyst and a preparation method and application thereof. The sulfur-resistant ultra-low temperature manganese-based denitration catalyst prepared by the preparation method of the present invention can simultaneously achieve good sulfur resistance, excellent ultra-low temperature denitration performance, reasonable economic cost, and high catalyst mechanical strength resulting in a long service life.

[0008] In order to achieve the above technical objectives, in a first aspect, the present invention provides a method for preparing a sulfur-resistant ultra-low temperature manganese-based denitration catalyst, comprising the following steps:

[0009] (1) adding a strontium source, a zirconium source and a ruthenium source to a solution to form an additive precursor solution, adding an organic solvent and a dispersant, mixing well, and then adding a precipitant to perform a precipitation reaction. After the reaction is completed, ultrasonic treatment, high-temperature calcination, and grinding are performed to obtain the corresponding oxide of the catalyst additive;

[0010] (2) dispersing the manganese source, the iron source, the corresponding oxide of the catalyst promoter obtained in step (1), and the pore-forming agent in water, and obtaining a catalyst precursor after intermittent ultrasonic treatment and aging;

[0011] (3) The catalyst precursor prepared in step (2) is calcined at low temperature to obtain matrix 1. Matrix 1 is added to the preheated acidic solution containing SO4 2- for etching treatment, and then dried to obtain matrix 2;

[0012] (4) Matrix 2 prepared in step (3) is impregnated and loaded in a solution containing an acidic organic ligand, and then dried and calcined at low temperature to obtain an anti-sulfur ultra-low temperature manganese-based denitration catalyst.

[0013] The preparation method of the above anti-sulfur ultra-low temperature manganese-based denitration catalyst promotes and improves the denitration performance and anti-sulfur effect of the catalyst under ultra-low temperature conditions through the synergistic cooperation of multiple technical features:

[0014] First, the present invention selects transition metals manganese and iron elements as active components, and uses strontium, zirconium and ruthenium elements as promoters for co-doping. By utilizing the interaction between the active components of manganese and iron and the promoters of strontium, zirconium and ruthenium, the NOx removal rate of the catalytic reaction is improved.

[0015] Manganese (Mn) is used as the main active component, mainly providing redox performance. The redox performance of manganese can promote the reduction reaction of NOx molecules, convert them into harmless nitrogen and water, and thus achieve the purpose of denitration.

[0016] Iron (Fe) is used as a co-active component, which can increase the number of acidic sites and reduction ability on the catalyst surface, play an anti-water role, improve the low-temperature activity of the catalyst, and further broaden its denitration temperature window. The unique electronic structure and redox performance of iron element enable the catalyst to activate reactant molecules at a lower temperature and reduce the activation energy of the reaction. Iron element can also inhibit the oxidation reaction of SO2 in the catalyst, reduce the formation of sulfates, and protect the active sites of the catalyst. The addition of Fe further promotes the uniform distribution of Mn 4+ and the content of surface adsorbed oxygen, thereby significantly enhancing the denitration performance of the catalyst; inhibiting the sulfation of manganese atomic centers and improving the anti-sulfur ability of the catalyst.

[0017] Strontium (Sr) is used as an active promoter, which has a certain anti-sulfur poisoning ability, is beneficial to the formation of oxygen vacancies in the catalyst, and improves the low-temperature denitration activity; doping strontium element can cause more lattice defects to further enhance its activity.

[0018] Zirconium (Zr) as an active promoter can significantly improve the water resistance of the catalyst, effectively inhibit the adsorption of sulfur dioxide by the catalyst, and endow the catalyst with better sulfur and water resistance. Due to its high strength and high toughness, ZrO2 has good mechanical strength, a large specific surface area and pore structure, can provide more active sites, enhance the effect of catalytic reactions, and as a catalyst structural promoter, improve the strength and wear resistance of the catalyst. ZrO2 can also be used as an acidic active site regulator.

[0019] Ruthenium (Ru) as an active promoter has multiple valence states and strong corrosion resistance to acids, alkalis, etc. During the denitrification process, ruthenium will form various oxidation states, expanding the surface defects of the catalyst, increasing the active sites on the catalyst surface, and further enhancing the adsorption and transfer effects of NOx, NH3, and O2 on the catalyst surface. In addition, the ruthenium-containing composite oxide can remain stable under catalytic oxidation conditions containing water vapor, improve the water resistance of the catalyst, and thus extend the service life of the catalyst.

[0020] Second, the present invention selects an acidic organic ligand as a component of the catalyst. The acidic organic ligand can increase the acidic sites on the catalyst surface. Since SO2 is an acidic gas, according to the principle of acid-base neutralization, increasing the acidity of the catalyst surface can reduce the adsorption capacity of SO2 on the catalyst surface, thereby reducing the risk of sulfur poisoning and achieving the effect of sulfur resistance. At the same time, in the form of an acidic organic ligand adopted by the present invention, the acidic sites on the catalyst surface are increased, which is beneficial to the adsorption and reaction of reactant molecules; the hydrophobicity of the catalyst is enhanced, avoiding the active sites being covered by water molecules; at the same time, the adsorption of water molecules and sulfur oxides on the catalyst is inhibited, reducing the formation, attachment, and accumulation of sulfates.

[0021] Third, currently, many denitrification catalysts use carriers. The denitrification catalyst carrier relies on the specific surface area and pore structure to provide a good distribution environment for the active components, and at the same time maintains the mechanical strength and chemical stability of the catalyst. However, the present invention does not use porous ceramic carriers such as TiO2 carriers, modified TiO2-CNTs carriers, Al2O3, ZrO2, modified activated carbon, molecular sieve carriers, and vanadium slag carriers modified by molecular sieves. After the catalyst precursor is calcined at low temperature, the present invention uses strong acid etching to further form a matrix with a rich pore structure inside, endowing it with a specific surface area and pore structure. Strong acid etching can also increase the roughness of the catalyst surface, increase the specific surface area of the catalyst, and expose the active sites that were originally covered or buried deep; introduce SO4 2-Etch with acid to increase the active acid sites on the catalyst surface and enhance its activity. Integrate the pore-forming and sulfuric acid acidification processes to simplify the production process and improve efficiency. The metal sulfate formed on the outer layer can react with ammonia and nitrogen monoxide to decompose into sulfur dioxide and metal active sites, further enhancing the sulfur resistance of the catalyst. Utilize the porous nature of the acidic porous material to adsorb ammonium sulfate and ammonium bisulfate generated at low temperatures to prevent physical poisoning of the catalyst caused by the presence of sulfur dioxide at low temperatures. Subsequently, modify the substrate with a large pore structure using an acidic organic ligand to form a composite structure with pores inside and an acidic ligand coating outside.

[0022] Fourth, compared with the traditional catalyst preparation method of co-precipitation of promoter elements and active components, the present invention adopts a preparation process combining "precipitation-impregnation", and sets an operation mode of stepwise calcination of the promoter and the active metal. In the actual process, different temperatures are used for calcination in steps (1), (3), and (4) respectively. This can not only avoid the coking problem caused by the high-temperature calcination of the active component with the promoter element in the traditional co-precipitation method, but also facilitate the selection of appropriate calcination temperatures at different stages, especially during the calcination of the catalyst precursor, to increase the relative content of high-valent manganese and iron in the main active element and further form an amorphous state of manganese oxide, thereby improving the denitrification activity of the catalyst.

[0023] It is found that the calcination temperatures of manganese and iron elements are similar. Therefore, the present invention uses manganese and iron as the main active components of the catalyst, simplifies the process flow, improves the operability of the preparation process, and is also conducive to obtaining a catalyst with better catalytic performance. It should be noted that for ruthenium, it is introduced together with the strontium source and zirconium source in the promoter precursor stage of step (1), rather than with the manganese source and iron source in step (2), mainly considering that the calcination temperature of the promoter precursor is high, which is more conducive to the formation of solid solutions of the promoters strontium, zirconium, and ruthenium, generating more oxygen vacancies and acidic sites, improving the specific surface area catalytic activity and acid resistance of the catalyst, and reducing the catalytic reaction temperature window.

[0024] In the preparation method of the above sulfur-resistant ultra-low temperature manganese-based denitrification catalyst, multiple technical features work together to improve the physical structure characteristics of the catalyst product and further enhance the low-temperature catalytic performance of the catalyst:

[0025] In step (1), adding an organic solvent to the promoter precursor solution can provide an appropriate viscosity for the precipitation reaction system. Since the viscosity of the mixed solution affects the diffusion rate of ions in the system and the precipitation reaction, it can further regulate the ion diffusion rate and precipitation rate. The addition of a dispersant can promote the dispersion of promoter elements, which is conducive to obtaining a catalyst promoter with sufficient reaction and more uniform element distribution. In addition, ultrasonic treatment is performed on the material after the precipitation process. With the transient cavitation effect generated by ultrasonic waves, the aggregation of crystal nuclei is effectively inhibited, and the violent impact and physical stirring effects will significantly improve the dispersion of each element in the promoter precipitation, which can cooperate with the dispersant to provide a better dispersion effect. Both ultrasonic treatment and the decomposition of carbonate contribute to the formation of pores.

[0026] In step (2), the present invention is supplemented with intermittent ultrasonic treatment, which can not only make the active promoter fully penetrate inside and outside the main active component through sufficient ultrasonic time to achieve a better dispersion effect of the active component and promoter elements, but also avoid the collapse of the promoter pore channels and the destruction of the structure caused by continuous long-time ultrasonic treatment.

[0027] Combining the above technical features, the preparation method of the sulfur-resistant ultra-low temperature manganese-based denitration catalyst of the present invention can improve the crystal growth process and structure of the promoter and the dispersion between elements. The prepared catalyst has the characteristics of regular particle morphology, uniform particle size, uniform dispersion of each component of the catalyst, and rich and regular pore structure.

[0028] In a further example of the present invention, the acidic solution containing SO4 2- in step (3) is sulfuric acid. Sulfuric acid can provide abundant H + and SO4 2- ions. These ions play a key role in the etching process and can destroy part of the structure of the catalyst precursor to form a rich pore structure. The strong acid etching is specifically to place the matrix 1 after low-temperature calcination in an acidic solution containing SO4 2- with a concentration of 2 - 5 mol / L and at 60 - 80 °C for etching for 2 - 5 h. After etching and drying, the pore volume of matrix 2 is 0.45 - 0.6 cm 3 / g, and the specific surface area is 180 - 260 m 2 / g. The larger specific surface area is conducive to carrying the special functional group structure of acidic organic ligands and is conducive to the adsorption of gaseous NH3 by the catalyst, thereby promoting the denitration reaction. Further, the acidic solution containing SO4 2- is sulfuric acid (more than 90% of the volume of the acidic solution) plus a certain amount of copper sulfate (less than 10% of the volume of the acidic solution), mainly based on using the high-valent Cu 2+ to increase the weak acidic sites on the catalyst surface, thereby improving the low-temperature activity and sulfur and water resistance of the catalyst.

[0029] In a further example of the present invention, in the step (4), the acidic organic ligand is one or more of naphthalenedicarboxylic acid or pyrazoledicarboxylic acid, preferably 2,6-naphthalenedicarboxylic acid or 3,5-pyrazoledicarboxylic acid. Both naphthalenedicarboxylic acid and pyrazoledicarboxylic acid have strong acidity, which can increase the acidic sites on the catalyst surface, thereby inhibiting the adsorption of SO2 acidic gas. Since H2O is considered to be a promoter for the adsorption and conversion of SO2 to form sulfate, it is necessary to perform surface hydrophobic modification on the catalyst to avoid the adsorption of H2O on the catalyst surface. Compared with 2,5-thiophenedicarboxylic acid and 1,4-benzenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid has stronger hydrophobicity, which helps to inhibit the adsorption and conversion of SO2 and can enhance the stability of the manganese-based denitration catalyst. Therefore, 2,6-naphthalenedicarboxylic acid is preferably used. Specifically, 0.1 to 0.2 mol of the acidic organic ligand is added to 100 ml of a solvent for impregnation, and the impregnation time is 0.5 to 1 h, where the solvent is one or more of formic acid, acetic acid, methanol, ethanol, isopropanol, and N,N-dimethylformamide.

[0030] In a further example of the present invention, based on the metal elements of the catalyst, the molar ratio of the manganese source, iron source, strontium source, zirconium source, and ruthenium source is 70∶(15 - 25)∶(2 - 15)∶(3 - 10)∶(0.01 - 0.1), preferably 70∶(18 - 22)∶(8 - 12)∶(6 - 8)∶(0.05 - 0.08). Among them, the molar ratio of the manganese source is the highest. The manganese source can promote the adsorption and conversion of NOx at a relatively low temperature, improving the overall activity of the catalyst; the molar ratio of the iron source is second only to that of the manganese source. Adding an iron source can increase the number of acidic sites and the reduction ability on the catalyst surface, promoting the catalyst activity and further broadening its denitrification temperature window. By the synergy of manganese and iron elements and further controlling the manganese / iron ratio, the low-temperature performance, stability, and NH3 adsorption performance are taken into account. Further, when the molar ratio of the manganese source to the iron source is less than 70:(15 - 25), the denitrification efficiency decreases to a certain extent, and it has an adverse effect on the catalyst strength and service life. When the molar ratio of the manganese source to the iron source is greater than 70:(15 - 25), the overall range of the activity window decreases, but at a relatively high denitrification temperature of 150 °C, the denitrification efficiency decreases to a certain extent. This may be because the MnOx loading is too high, and MnOx is saturated and covers the catalyst surface or pores, covering the catalytically active surface acid centers, forming blockages and hindering the progress of the reaction, resulting in a decrease in the denitrification efficiency. The exploration and optimization of the ratio relationship between the active components and the promoter elements in the examples and comparative examples are beneficial to exert the synergistic catalytic effect of the active components and the promoter elements and increase the proportion of the high-valence states of the active components manganese and iron. In an alternative example of the present invention, based on the metal elements of the catalyst, the molar ratio of the manganese source, iron source, strontium source, zirconium source, and ruthenium source is 70∶(18 - 22)∶(8 - 12)∶(6 - 8)∶(0.05 - 0.08); in a preferred example of the present invention, the molar ratio of the manganese source, iron source, strontium source, zirconium source, and ruthenium source is preferably 70∶20∶10∶7∶0.06.

[0031] In a further example of the present invention, the high-temperature calcination temperature in step (1) is 800 - 1200 °C, and the time is 3 - 8 h; the calcination temperature of the promoter precursor is higher than that of the catalyst precursor. Further optionally, the calcination temperature of the promoter precursor in step (1) is 900 - 1100 °C.

[0032] In a further example of the present invention, the low-temperature calcination temperature in step (3) is 300 - 500 °C, and the time is 2 - 5 h;

[0033] The low-temperature calcination temperature in step (4) is 300 - 500 °C, and the time is 2 - 5 h.

[0034] Compared with the calcination temperature of the promoter precursor component, the calcination temperature of the catalyst precursor is lower, which is beneficial to maintaining the content of elements in the active component corresponding to the high activity valence state and improving the denitrification catalytic activity of the catalyst under low temperature conditions.

[0035] In a further example of the present invention, the sources of the manganese source, iron source, strontium source, zirconium source and ruthenium source are optimized. The strontium source in the step (1) includes one or two of strontium chloride and strontium nitrate;

[0036] And / or, the zirconium source in the step (1) includes one or two of zirconium nitrate and zirconium chloride;

[0037] And / or, the ruthenium source in the step (1) includes one or two of ruthenium trichloride and ruthenium nitrate;

[0038] And / or, the manganese source in the step (2) includes at least one of manganese acetate, manganese nitrate and manganese sulfate;

[0039] And / or, the iron source in the step (2) includes at least one of iron nitrate, iron sulfate and iron chloride.

[0040] In the actual process, those skilled in the art can select according to needs.

[0041] In a further example of the present invention, the organic solvent in the step (1) includes at least one of n-butanol, n-propanol and glycerol; Examples of the present invention illustrate the preparation of sulfur-resistant ultra-low temperature manganese-based denitrification catalysts using different organic solvents. Further, the addition amount of the organic solvent is 20% - 50% of the volume of the promoter precursor solution. By adding an appropriate proportion of the organic solvent to the promoter precursor solution, the preparation system can be made to present a state with a certain viscosity, which is beneficial to regulating the rate of the subsequent precipitation reaction. In an optional example of the present invention, the addition amount of the organic solvent is preferably 30% - 50% of the volume of the promoter precursor solution.

[0042] In a further example of the present invention, the dispersant in the step (1) includes at least one of sulfonated polystyrene, sodium polyacrylate and polyacrylamide; Examples of the present invention illustrate the use of different dispersants for sulfur-resistant ultra-low temperature manganese-based denitrification catalysts. Further, the addition amount of the dispersant is 0.3% - 2.0% of the mass of the corresponding oxide of the catalyst promoter. By exploring the dosage of the dispersant, it is convenient to comprehensively regulate the rate of the precipitation reaction in combination with the addition of the organic solvent; it should be noted that in the actual process, the dosage of the dispersant to be added can be determined by the amount of the catalyst promoter obtained through theoretical calculation. In an optional example of the present invention, the addition amount of the dispersant is preferably 0.5% - 1.5% of the mass of the corresponding oxide of the catalyst promoter.

[0043] In a further example of the present invention, in step (1), the precipitant is an aqueous solution of an alkaline carbonate, preferably at least one of sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, ammonium carbonate, and ammonium bicarbonate, and more preferably sodium carbonate. Carbonates will form a certain pore structure during high-temperature calcination.

[0044] It should be noted that the present invention does not limit the way of adding the precipitant. It can be added dropwise to improve the operability of the precipitation reaction, and those skilled in the art can select a suitable way to add the precipitant according to needs.

[0045] In a further example of the present invention, in step (2), the pore-forming agent is at least one of carboxymethyl cellulose, polyethylene oxide, polyethylene glycol, activated carbon, urea, starch, polyacrylamide, and polyvinyl alcohol, and the addition amount of the pore-forming agent is 10% - 20% of the mass of the corresponding oxide of the catalyst promoter; it should be noted that most of the above pore-forming agents also have the functions of thickening and promoting the dispersion of catalyst components.

[0046] In a further example of the present invention, in step (4), a coupling agent can be selectively added to the solution, preferably at least one of silane coupling agents KH540, KH550, and KH560, accounting for less than 10% of the solution volume. The silane coupling agent increases the wettability and dispersibility of the active component and the acidic organic ligand, enabling better binding between its components and improving the overall performance of the catalyst.

[0047] In a further example of the present invention, in step (1), the pH value of the material after the precipitation reaction is 9 - 11. It should be noted that the present invention does not limit the dosage of the precipitant. To promote the full precipitation of the promoter element, an excessive amount of precipitant can be selectively added; in actual operation, the appropriate end point of the reaction can be determined according to the pH value of the material after the precipitation reaction, or a precipitant about 1.5 - 2 times the amount of precipitant required for the promoter element can be considered to be added to promote the reaction to completion.

[0048] In a further example of the present invention, in step (1), the temperature of the ultrasound is 60 - 80 °C, the power is 40 - 240 W, and the time is 2 - 5 h; by performing continuous ultrasound operation at a suitable temperature, power, and duration, it is beneficial to control the crystallization rate of the promoter and ultimately optimize the catalytic performance of the prepared catalyst.

[0049] In a further example of the present invention, in step (1), the grinding speed is 300 - 500 r / min, and the time is 10 - 60 min. It is further preferably ground and sieved to 20 - 50 mesh.

[0050] In a further example of the present invention, the power of the intermittent ultrasound in step (2) is 50 - 100 W, with ultrasound applied for 30 - 90 min each time and stopped for 15 - 25 min, and the intermittent ultrasound is applied 3 - 5 times. The intermittent ultrasound is beneficial for the active components to be fully dispersed and impregnated in the catalyst promoter, and at the same time is beneficial for improving the pore structure of the catalyst.

[0051] In a further example of the present invention, the aging temperature in step (2) is 15 - 30 °C and the time is 5 - 10 h.

[0052] Optionally, step (2) further includes solid-liquid separation of the material after the aging treatment. Solid-liquid separation can be optionally carried out by operations such as centrifugation and suction filtration, and further optionally suction filtration. Further optionally, step (2) further includes drying the separated solid phase. The drying temperature can be optionally 100 - 120 °C and the drying time can be optionally 5 - 20 h.

[0053] In a second aspect, the present invention also provides an anti-sulfur ultra-low temperature manganese-based denitration catalyst. The anti-sulfur ultra-low temperature manganese-based denitration catalyst is prepared by using the preparation method of the anti-sulfur ultra-low temperature manganese-based denitration catalyst described in the first aspect. In terms of metal elements, the molar ratio of the manganese source, iron source, strontium source, zirconium source and ruthenium source in the catalyst is 70∶(15 - 25)∶(2 - 15)∶(3 - 10)∶(0.01 - 0.1), preferably 70∶(18 - 22)∶(8 - 12)∶(6 - 8)∶(0.05 - 0.08).

[0054] In a third aspect, the present invention also provides an application of a catalyst prepared by using the preparation method of the anti-sulfur ultra-low temperature manganese-based denitration catalyst described in the first aspect or the anti-sulfur ultra-low temperature manganese-based denitration catalyst described in the second aspect in NH3-SCR. The anti-sulfur ultra-low temperature manganese-based denitration catalyst of the present invention exhibits excellent NOx denitration catalytic activity under the condition of ≤150 °C, and has important practical application value.

[0055] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0056] (1) In the preparation method of the anti-sulfur ultra-low temperature manganese-based denitration catalyst of the present invention, the form of acidic organic ligands is adopted, which improves the acidic sites on the catalyst surface, is beneficial to the adsorption and reaction of reactant molecules; enhances the hydrophobicity of the catalyst, avoids the active sites being covered by water molecules; at the same time inhibits the adsorption of water molecules and sulfur oxides on the catalyst, and reduces the formation, attachment and accumulation of manganese sulfate compounds.

[0057] (2) In the preparation method of the sulfur-resistant ultra-low temperature manganese-based denitration catalyst of the present invention, porous ceramic carriers such as TiO2 carrier, modified TiO2-CNTs carrier, Al2O3, ZrO2, modified activated carbon, molecular sieve carrier, and vanadium slag carrier modified by molecular sieve are not used. In the preparation method of the sulfur-resistant ultra-low temperature manganese-based denitration catalyst of the present invention, after the catalyst precursor is calcined at low temperature, a matrix with a rich pore structure is formed inside by means of strong acid etching. It has a large specific surface area and pore structure, which is conducive to carrying the special functional group structure of acidic organic ligands and is conducive to the adsorption of gaseous NH3 by the catalyst, thereby promoting the progress of the denitration reaction.

[0058] (3) In the preparation method of the sulfur-resistant ultra-low temperature manganese-based denitration catalyst of the present invention, precipitation-impregnation-stepwise calcination is used, and an organic solvent, a dispersant and the first ultrasonic treatment are combined in the precipitation process, and intermittent ultrasonic treatment is adopted in the impregnation process to uniformly impregnate the active elements inside and outside the catalyst assistant; the calcination temperature of the assistant precursor is high, which is more conducive to the formation of solid solutions of the assistants strontium, zirconium and ruthenium, generating more oxygen vacancies and acidic sites, improving the specific surface area catalytic activity and acid resistance of the catalyst, and reducing the catalytic reaction temperature window. The sulfur-resistant ultra-low temperature manganese-based denitration catalyst prepared by the preparation method of the present invention has rich pores, a large specific surface area, and uniform dispersion of active substances and assistant elements, and has excellent ultra-low temperature catalytic activity.

[0059] (4) The present invention does not use rare earth elements such as Ce, Sm, La for doping, and adding a small amount of ruthenium-containing substances has good economy.

[0060] (5) The sulfur-resistant ultra-low temperature manganese-based denitration catalyst of the present invention exhibits excellent NOx denitration catalytic activity under the condition of ≤150 °C, and the best applicable temperature under ultra-low temperature conditions is 120-150 °C. It should be noted that this catalyst can not only work at ≤150 °C, and its denitration efficiency is close to 100% at 150-300 °C. In addition, the present invention also pays attention to the catalyst strength (axial compressive strength 3.2-3.8 MPa, radial compressive strength 1.1-1.3 MPa), which has important practical application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] The specification drawings forming a part of this application are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0062] Figure 1 Shows the SEM image of Example 4 of the present invention at a scale of 50 μm;

[0063] Figure 2 Shows the SEM image of Example 4 of the present invention at a scale of 2 μm. Detailed implementation mode

[0064] For the convenience of understanding the present invention, the present invention will be described more comprehensively below, and preferred embodiments of the present invention are given. However, it should be understood that these embodiments are only for more detailed description and should not be construed as limiting the present invention in any form, that is, it is not intended to limit the protection scope of the present invention.

[0065] Catalyst specific surface area: An aperture and specific surface area analyzer is used. Nitrogen and helium are used as the adsorption gas and carrier gas, and the specific surface area is calculated by the BET method. A V-Sorb2800P type aperture and specific surface area analyzer is used.

[0066] Denitration efficiency measurement: The gas consists of NOx, NH3, O2 and carrier gas N2, and the space velocity is 7500 h -1 , the NOx concentration is 1200 mg / m 3 , the NH3 / NOx molar ratio = 1, the O2 concentration: 10%, and the system starts to collect and test the denitration efficiency at 80 / 120 / 150 °C after the ventilation operation is stable. Denitration efficiency = (NO concentration before denitration - NO concentration after denitration) / NO concentration before denitration × 100%.

[0067] Sulfur resistance performance measurement: The gas consists of NOx, NH3, SO2, O2 and carrier gas N2, and the space velocity is 7500 h -1 , the NOx concentration is 1200 mg / m 3 , the NH3 / NOx molar ratio = 1, the O2 concentration: 10%, and the SO2 concentration: 500 mg / m 3 ; the system starts to collect and test the denitration efficiency at 150 °C after the ventilation operation is stable.

[0068] Unless otherwise defined, the technical terms used in the following embodiments have the same meanings as commonly understood by those skilled in the art to which the present invention pertains. The test reagents used in the following embodiments are all conventional reagents unless otherwise specified; the experimental methods are all conventional methods unless otherwise specified.

[0069] Example 1

[0070] This example provides a preparation method of a sulfur-resistant ultra-low temperature manganese-based denitration catalyst, which includes the following steps:

[0071] (1) In 1000 ml of deionized water, add strontium source, zirconium source and ruthenium source additives (5.33 g of strontium chloride hexahydrate, 10.18 g of zirconium nitrate, and 0.02 g of ruthenium trichloride are added respectively, and the corresponding molar ratio is 2:3:0.01) to form an additive precursor solution. Subsequently, add n-butanol, an organic solvent accounting for 30% by volume of the additive precursor solution, and add sulfonated polystyrene, a dispersant accounting for 0.5% of the mass of the corresponding oxides of the strontium source, zirconium source and ruthenium source additives. After mixing evenly, add precipitant sodium carbonate for precipitation reaction until the pH reaches 9. Control the temperature of the mixture at 60 °C and perform ultrasonic treatment at a power of 40 W for 2 h while stirring to form a suspended additive precursor; wash, filter by suction, and dry the additive precursor, then calcine it at a high temperature of 800 °C for 8 h and grind it at 300 r / min for 30 min to obtain the corresponding oxides of the catalyst additive;

[0072] (2) Disperse manganese source, iron source (171.56 g of manganese acetate tetrahydrate and 36.28 g of iron nitrate are added respectively, and the corresponding molar ratio is 70:15), the corresponding oxides of the catalyst additive prepared in step (1), and carboxymethyl cellulose, a pore-forming agent accounting for 10% of the mass of the corresponding oxides of the catalyst additive in 1000 ml of deionized water. After intermittent ultrasonic treatment at a power of 50 W for 3 times (ultrasonic for 30 min and stop for 15 min each time) and aging at 15 °C for 10 h, a catalyst precursor is obtained;

[0073] (3) Calcinate the catalyst precursor prepared in step (2) at a low temperature of 300 °C for 2 h to obtain matrix 1. Add matrix 1 to a sulfuric acid solution with a concentration of 2 mol / L at 60 °C for etching for 2 h, and obtain matrix 2 after drying;

[0074] (4) Immerse matrix 2 prepared in step (3) in a 100 ml methanol solution containing 2 ml of coupling agent KH540 and 0.1 mol of acidic organic ligand 2,6-naphthalenedicarboxylic acid for 0.5 h, and obtain an anti-sulfur ultra-low temperature manganese-based denitration catalyst after drying and calcining at a low temperature of 500 °C for 5 h.

[0075] Example 2

[0076] This example provides a preparation method of an anti-sulfur ultra-low temperature manganese-based denitration catalyst, including the following steps:

[0077] (1) In 1000 ml of deionized water, add strontium source, zirconium source and ruthenium source additives (16.93 g of strontium nitrate, 13.98 g of zirconium chloride, and 0.16 g of ruthenium nitrate are added respectively, and the corresponding molar ratio is 8:6:0.05) to form an additive precursor solution. Subsequently, add n-propanol, an organic solvent accounting for 20% of the volume of the additive precursor solution, and add sulfonated polystyrene, a dispersant accounting for 0.3% of the mass of the corresponding oxides of the strontium source, zirconium source and ruthenium source additives. After mixing evenly, add precipitant potassium carbonate for precipitation reaction until the pH reaches 10. Control the temperature of the mixture at 70 °C, perform ultrasonic treatment at a power of 120 W for 3 h, and stir simultaneously to form a suspended additive precursor; wash, filter by suction, and dry the additive precursor, and then calcine it at 900 °C for 6 h and grind it at 400 r / min for 20 min to obtain the corresponding oxides of the catalyst additive;

[0078] (2) Disperse manganese source, iron source (105.7 g of manganese sulfate and 71.98 g of iron sulfate are added respectively, and the corresponding molar ratio is 70:18), the corresponding oxides of the catalyst additive prepared in step (1), and carboxymethyl cellulose, a pore-forming agent accounting for 15% of the mass of the corresponding oxides of the catalyst additive, in 1000 ml of deionized water. After aging at 20 °C for 5 h with intermittent ultrasonic treatment at a power of 75 W, ultrasonic for 60 min and stop for 25 min each time, and intermittent ultrasonic treatment for 5 times, a catalyst precursor is obtained;

[0079] (3) Calcinate the catalyst precursor prepared in step (2) at a low temperature of 300 °C for 5 h to obtain matrix 1. Add matrix 1 to a sulfuric acid solution with a concentration of 3 mol / L at 70 °C for etching for 3 h, and obtain matrix 2 after drying;

[0080] (4) Immerse matrix 2 prepared in step (3) in a 100 ml ethanol solution containing 5 ml of coupling agent KH550 and 0.15 mol of acidic organic ligand 3,5-pyrazoledicarboxylic acid for 0.6 h, and obtain an anti-sulfur ultra-low temperature manganese-based denitration catalyst after drying and low-temperature calcination at 500 °C for 2 h.

[0081] Example 3

[0082] This example provides a preparation method of an anti-sulfur ultra-low temperature manganese-based denitration catalyst, including the following steps:

[0083] (1) In 1000 ml of deionized water, strontium source, zirconium source and ruthenium source additives (26.66 g of strontium chloride hexahydrate, 18.64 g of zirconium chloride, and 0.12 g of ruthenium trichloride are added respectively, with corresponding molar ratio of 10:8:0.06) are added to form an additive precursor solution. Subsequently, glycerol, an organic solvent accounting for 40% by volume of the additive precursor solution, is added, and polyacrylamide, a dispersant accounting for 1.5% of the mass of the corresponding oxides of the strontium source, zirconium source and ruthenium source additives, is added. After mixing evenly, sodium bicarbonate, a precipitant, is added for precipitation reaction until the pH reaches 11. The temperature of the mixture is controlled at 80 °C, and ultrasonic treatment is carried out at a power of 120 W for 2 h while stirring to form a suspended additive precursor; the additive precursor is washed, filtered by suction, dried, and then calcined at a high temperature of 1100 °C for 3 h and ground at 500 r / min for 60 min to obtain the corresponding oxides of the catalyst additive;

[0084] (2) Manganese source, iron source (105.7 g of manganese sulfate and 35.68 g of ferric chloride are added respectively, with corresponding molar ratio of 70:22), the corresponding oxides of the catalyst additive prepared in step (1), and carboxymethyl cellulose, a pore-forming agent accounting for 15% of the mass of the corresponding oxides of the catalyst additive, are dispersed in 1000 ml of deionized water. After intermittent ultrasonic treatment at a power of 100 W for 4 times, with each ultrasonic treatment for 90 min and then stopping for 20 min, and aging at 25 °C for 7 h, a catalyst precursor is obtained;

[0085] (3) The catalyst precursor prepared in step (2) is calcined at a low temperature of 400 °C for 3 h to obtain matrix 1. Matrix 1 is added to a sulfuric acid solution with a concentration of 5 mol / L at 60 °C for etching for 2 h, and after drying, matrix 2 is obtained;

[0086] (4) Matrix 2 prepared in step (3) is impregnated and loaded in a 100 ml isopropanol solution containing 7 ml of coupling agent KH560 and 0.2 mol of acidic organic ligand 2,6-naphthalenedicarboxylic acid for 0.7 h. After drying and low-temperature calcination at 500 °C for 3 h, an anti-sulfur ultra-low temperature manganese-based denitration catalyst is obtained.

[0087] Example 4

[0088] This example provides a preparation method of an anti-sulfur ultra-low temperature manganese-based denitration catalyst, which includes the following steps:

[0089] (1) In 1000 ml of deionized water, add strontium source, zirconium source and ruthenium source additives (26.66 g of strontium chloride hexahydrate, 23.75 g of zirconium nitrate, and 0.12 g of ruthenium trichloride are added respectively, and the corresponding molar ratio is 10:7:0.06) to form an additive precursor solution. Subsequently, add n-butanol, an organic solvent accounting for 50% by volume of the additive precursor solution, and add sodium polyacrylate, a dispersant accounting for 1.5% of the mass of the corresponding oxides of the strontium source, zirconium source and ruthenium source additives. After mixing evenly, add precipitant potassium bicarbonate for precipitation reaction until the pH reaches 10. Control the temperature of the mixture at 60 °C, perform ultrasonic treatment at a power of 180 W for 4 h, and stir simultaneously to form a suspended additive precursor; wash, filter by suction, and dry the additive precursor, then calcine it at a high temperature of 1100 °C for 4 h, and grind it at 400 r / min for 50 min to obtain the corresponding oxides of the catalyst additive;

[0090] (2) Disperse manganese source, iron source (105.7 g of manganese sulfate and 32.44 g of iron chloride are added respectively, and the corresponding molar ratio is 70:20), the corresponding oxides of the catalyst additive prepared in step (1), and polyethylene oxide, a pore-forming agent accounting for 20% of the mass of the corresponding oxides of the catalyst additive, in 1000 ml of deionized water. After intermittent ultrasonic treatment at a power of 100 W for 4 times, with each ultrasonic treatment for 60 min and then stopping for 20 min, and aging at 30 °C for 5 h, a catalyst precursor is obtained;

[0091] (3) Calcinate the catalyst precursor prepared in step (2) at a low temperature of 400 °C for 4 h to obtain matrix 1. Add matrix 1 to a sulfuric acid solution with a concentration of 4 mol / L at 80 °C and etch for 4 h, and then obtain matrix 2 after drying;

[0092] (4) Immerse matrix 2 prepared in step (3) in 100 ml of formic acid solution containing 7 ml of coupling agent KH550 and 0.15 mol of acidic organic ligand 2,6-naphthalenedicarboxylic acid for 0.8 h, and then obtain an anti-sulfur ultra-low temperature manganese-based denitration catalyst after drying and low-temperature calcination at 400 °C for 4 h.

[0093] Example 5

[0094] This example provides a preparation method of an anti-sulfur ultra-low temperature manganese-based denitration catalyst, including the following steps:

[0095] (1) In 1000 ml of deionized water, add strontium source, zirconium source and ruthenium source additives (25.4 g of strontium nitrate, 18.64 g of zirconium chloride, and 0.17 g of ruthenium trichloride are added respectively, and the corresponding molar ratio is 12:8:0.08) to form an additive precursor solution. Subsequently, add n-propanol, an organic solvent accounting for 40% of the volume of the additive precursor solution, and add sulfonated polystyrene, a dispersant accounting for 2% of the mass of the corresponding oxides of the strontium source, zirconium source and ruthenium source additives. After mixing evenly, add ammonium carbonate, a precipitant, for precipitation reaction until the pH reaches 10. Control the temperature of the mixture at 70 °C and ultrasonically treat it at a power of 240 W for 5 h while stirring to form a suspended additive precursor; wash, filter by suction, and dry the additive precursor, then calcine it at a high temperature of 1200 °C for 3 h and grind it at 300 r / min for 40 min to obtain the corresponding oxides of the catalyst additive;

[0096] (2) Disperse manganese source, iron source (125.27 g of manganese nitrate and 99.97 g of ferric sulfate are added respectively, and the corresponding molar ratio is 70:25), the corresponding oxides of the catalyst additive prepared in step (1), and polyethylene glycol, a pore-forming agent accounting for 15% of the mass of the corresponding oxides of the catalyst additive, in 1000 ml of deionized water. After intermittent ultrasonic treatment at a power of 50 W, with each ultrasonic treatment for 90 min and then stopping for 15 min, for 3 times, and aging at 15 °C for 5 h, a catalyst precursor is obtained;

[0097] (3) Calcinate the catalyst precursor prepared in step (2) at a low temperature of 500 °C for 5 h to obtain matrix 1. Add matrix 1 to a sulfuric acid solution with a concentration of 2 mol / L and a temperature of 80 °C for etching for 5 h, and then obtain matrix 2 after drying;

[0098] (4) Immerse matrix 2 prepared in step (3) in 100 ml of acetic acid solution containing 10 ml of coupling agent KH560 and 0.1 mol of acidic organic ligand 3,5-pyrazoledicarboxylic acid for impregnation loading for 1 h. After drying and calcining at a low temperature of 300 °C for 5 h, an anti-sulfur ultra-low temperature manganese-based denitrification catalyst is obtained.

[0099] Example 6

[0100] This example provides a preparation method of an anti-sulfur ultra-low temperature manganese-based denitrification catalyst, including the following steps:

[0101] (1) In 1000 ml of deionized water, add strontium source, zirconium source and ruthenium source additives (31.74 g of strontium nitrate, 13.98 g of zirconium chloride, and 0.21 g of ruthenium trichloride are added respectively, and the corresponding molar ratio is 15:6:0.1) to form an additive precursor solution. Subsequently, add n-butanol, an organic solvent accounting for 30% by volume of the additive precursor solution, and add sodium polyacrylate, a dispersant accounting for 0.5% of the mass of the corresponding oxides of the strontium source, zirconium source and ruthenium source additives. After mixing evenly, add precipitant ammonium bicarbonate for precipitation reaction until the pH reaches 11. Control the temperature of the mixture at 60 °C, perform ultrasonic treatment at a power of 180 W for 3 h, and stir simultaneously to form a suspended additive precursor; wash, filter by suction, and dry the additive precursor, then calcine it at a high temperature of 1000 °C for 6 h, and grind it at 400 r / min for 30 min to obtain the corresponding oxides of the catalyst additive;

[0102] (2) Disperse manganese source, iron source (105.7 g of manganese sulfate and 35.68 g of ferric chloride are added respectively, and the corresponding molar ratio is 70:22), the corresponding oxides of the catalyst additive prepared in step (1), and polyethylene glycol, a pore-forming agent accounting for 15% of the mass of the corresponding oxides of the catalyst additive, in 1000 ml of deionized water. After intermittent ultrasonic treatment with a power of 100 W, ultrasonic for 60 min each time and stop for 15 min, and perform intermittent ultrasonic treatment 3 times and age at 30 °C for 7 h to obtain a catalyst precursor;

[0103] (3) Calcinate the catalyst precursor prepared in step (2) at a low temperature of 500 °C for 2 h to obtain substrate 1. Add substrate 1 to a sulfuric acid solution with a concentration of 5 mol / L and a temperature of 80 °C for etching for 2 h, and obtain substrate 2 after drying;

[0104] (4) Immerse and load substrate 2 prepared in step (3) in a 100 ml N,N-dimethylformamide solution containing 10 ml of coupling agent KH560 and 0.12 mol of acidic organic ligand 2,6-naphthalenedicarboxylic acid for 0.9 h. After drying and calcining at a low temperature of 450 °C for 4 h, an anti-sulfur ultra-low temperature manganese-based denitrification catalyst is obtained.

[0105] Example 7

[0106] This example provides a preparation method of an anti-sulfur ultra-low temperature manganese-based denitrification catalyst, including the following steps:

[0107] (1) In 1000 ml of deionized water, strontium source, zirconium source and ruthenium source additives (21.16 g of strontium nitrate, 33.93 g of zirconium nitrate, and 0.1 g of ruthenium trichloride are added respectively, and the corresponding molar ratio is 10∶10∶0.05) are added to form an additive precursor solution. Subsequently, glycerol, an organic solvent accounting for 20% by volume of the additive precursor solution, and polyacrylamide, a dispersant accounting for 1% of the mass of the corresponding oxides of the strontium source, zirconium source and ruthenium source additives, are added. After mixing evenly, precipitating agent sodium carbonate is added for precipitation reaction until the pH reaches 10. The temperature of the mixture is controlled at 60 °C, ultrasonic treatment is carried out at a power of 120 W for 2 h, and stirring is carried out simultaneously to form a suspended additive precursor; the additive precursor is washed, filtered by suction, dried and then calcined at 800 °C for 8 h and ground at 500 r / min for 20 min to obtain the corresponding oxides of the catalyst additive;

[0108] (2) Manganese source, iron source (105.7 g of manganese sulfate and 59.98 g of iron sulfate are added respectively, and the corresponding molar ratio is 70∶15), the corresponding oxides of the catalyst additive prepared in step (1), and polyethylene glycol, a pore-forming agent accounting for 15% of the mass of the corresponding oxides of the catalyst additive, are dispersed in 1000 ml of deionized water. After intermittent ultrasonic treatment with a power of 50 W, ultrasonic treatment for 30 min each time and stopping for 15 min, and intermittent ultrasonic treatment for 5 times, and aging at 20 °C for 10 h, a catalyst precursor is obtained;

[0109] (3) The catalyst precursor prepared in step (2) is calcined at a low temperature of 400 °C for 2 h to obtain substrate 1. Substrate 1 is added to a mixed solution of sulfuric acid - copper sulfate with a concentration of 5 mol / L and a temperature of 60 °C (the volume ratio of sulfuric acid to copper sulfate is 9:1) for etching for 2 h, and after drying, substrate 2 is obtained;

[0110] (4) Substrate 2 prepared in step (3) is impregnated and loaded in a 100 ml formic acid solution containing 10 ml of coupling agent KH560 and 0.17 mol of acidic organic ligand 3,5 - pyrazoledicarboxylic acid for 0.6 h. After drying and low-temperature calcination at 350 °C for 5 h, an anti-sulfur ultra-low temperature manganese-based denitrification catalyst is obtained.

[0111] Comparative Example 1

[0112] Compared with Example 1, the difference is only that the ruthenium source is not added in step (1). The specific process is as follows:

[0113] (1) In 1000 ml of deionized water, strontium source and zirconium source additives (5.33 g of strontium chloride hexahydrate and 10.18 g of zirconium nitrate are added respectively, and the corresponding molar ratio is 2:3) are added to form an additive precursor solution. Subsequently, n-butanol, an organic solvent accounting for 30% of the volume of the additive precursor solution, and sulfonated polystyrene, a dispersant accounting for 0.5% of the mass of the corresponding oxides of the strontium source and zirconium source additives, are added. After mixing evenly, precipitating agent sodium carbonate is added for precipitation reaction until the pH reaches 9. The temperature of the mixture is controlled at 60 °C, and ultrasonic treatment is carried out at a power of 40 W for 2 h while stirring to form a suspended additive precursor; the additive precursor is washed, filtered by suction, dried, and then calcined at 800 °C for 8 h and ground at 300 r / min for 30 min to obtain the corresponding oxides of the catalyst additive;

[0114] Steps (2), (3), and (4) are the same as those in Example 1.

[0115] Comparative Example 2

[0116] Compared with Example 1, the difference is only that no ruthenium source is added in step (1), but a ruthenium source is added in step (2). The specific process is as follows:

[0117] (1) In 1000 ml of deionized water, strontium source and zirconium source additives (5.33 g of strontium chloride hexahydrate and 10.18 g of zirconium nitrate are added respectively, and the corresponding molar ratio is 2:3) are added to form an additive precursor solution. Subsequently, n-butanol, an organic solvent accounting for 30% of the volume of the additive precursor solution, and sulfonated polystyrene, a dispersant accounting for 0.5% of the mass of the corresponding oxides of the strontium source and zirconium source additives, are added. After mixing evenly, precipitating agent sodium carbonate is added for precipitation reaction until the pH reaches 9. The temperature of the mixture is controlled at 60 °C, and ultrasonic treatment is carried out at a power of 40 W for 2 h while stirring to form a suspended additive precursor; the additive precursor is washed, filtered by suction, dried, and then calcined at 800 °C for 8 h and ground at 300 r / min for 30 min to obtain the corresponding oxides of the catalyst additive.

[0118] (2) Manganese source, iron source, ruthenium source (171.56 g of manganese acetate tetrahydrate, 36.28 g of iron nitrate, and 0.02 g of ruthenium trichloride are added respectively, and the corresponding molar ratio is 70:15:0.01), the corresponding oxides of the catalyst additive prepared in step (1), and carboxymethyl cellulose, a pore-forming agent accounting for 10% of the mass of the corresponding oxides of the catalyst additive, are dispersed in 1000 ml of deionized water. After ultrasonic treatment at a power of 50 W, with ultrasonic treatment for 30 min and then stopping for 15 min, intermittent ultrasonic treatment is carried out 3 times, and aging is carried out at 15 °C for 10 h to obtain a catalyst precursor;

[0119] Steps (3) and (4) are the same as those in Example 1.

[0120] Comparative Example 3

[0121] Compared with Example 2, the difference is only in the molar ratio of Mn and Fe in step (2). The specific process is as follows:

[0122] (1) In 1000 ml of deionized water, add strontium source, zirconium source and ruthenium source additives (16.93 g of strontium nitrate, 13.98 g of zirconium chloride, and 0.16 g of ruthenium nitrate are added respectively, and the corresponding molar ratio is 8:6:0.05) to form an additive precursor solution. Subsequently, add n-propanol, an organic solvent accounting for 20% by volume of the additive precursor solution, and add sulfonated polystyrene, a dispersant accounting for 0.3% of the mass of the corresponding oxides of the strontium source, zirconium source and ruthenium source additives. After mixing evenly, add precipitant potassium carbonate for precipitation reaction until the pH is 10. Control the temperature of the mixture at 70 °C, perform ultrasonic treatment at a power of 120 W for 3 h, and stir simultaneously to form a suspended additive precursor; wash, filter and dry the additive precursor, then calcine it at 900 °C for 6 h and grind it at 400 r / min for 20 min to obtain the corresponding oxides of the catalyst additives;

[0123] (2) Disperse manganese source, iron source (95.13 g of manganese sulfate and 99.97 g of iron sulfate are added respectively, and the corresponding molar ratio is 63:25), the corresponding oxides of the catalyst additives prepared in step (1), and carboxymethyl cellulose, a pore-forming agent accounting for 15% of the mass of the corresponding oxides of the catalyst additives, in 1000 ml of deionized water. After intermittent ultrasonic treatment at a power of 75 W, ultrasonic for 60 min each time and stop for 25 min, for 5 times, and aging at 20 °C for 5 h, a catalyst precursor is obtained;

[0124] Steps (3) and (4) are the same as in Example 2.

[0125] Comparative Example 4

[0126] Compared with Example 2, the difference is only in the molar ratio of Mn and Fe in step (2). The specific process is as follows:

[0127] (1) In 1000 ml of deionized water, add strontium source, zirconium source and ruthenium source additives (16.93 g of strontium nitrate, 13.98 g of zirconium chloride, and 0.16 g of ruthenium nitrate are added respectively, and the corresponding molar ratio is 8:6:0.05) to form an additive precursor solution. Subsequently, add n-propanol, an organic solvent accounting for 20% by volume of the additive precursor solution, and add sulfonated polystyrene, a dispersant accounting for 0.3% of the mass of the corresponding oxides of the strontium source, zirconium source and ruthenium source additives. After mixing evenly, add precipitant potassium carbonate for precipitation reaction until the pH is 10. Control the temperature of the mixture at 70 °C, perform ultrasonic treatment at a power of 120 W for 3 h, and stir simultaneously to form a suspended additive precursor; wash, filter and dry the additive precursor, then calcine it at 900 °C for 6 h and grind it at 400 r / min for 20 min to obtain the corresponding oxides of the catalyst additives;

[0128] (2) Add 110.23 g of manganese source and 59.98 g of iron source (manganese sulfate and iron sulfate respectively), with the corresponding molar ratio of 73:15, and 15% by mass of the corresponding oxide of the catalyst promoter and the pore-forming agent carboxymethyl cellulose into 1000 ml of deionized water. Disperse them, and after intermittent ultrasonic treatment with a power of 75 W, ultrasonic for 60 min each time, stop for 25 min, and repeat 5 times, and age at 20 °C for 5 h to obtain the catalyst precursor;

[0129] Steps (3) and (4) are the same as those in Example 2.

[0130] Comparative Example 5

[0131] Compared with Example 3, the difference is only the addition amount of the acidic organic ligand in step (4). The specific process is as follows:

[0132] (4) Immerse and load the matrix 2 prepared in step (3) in a 100 ml isopropanol solution containing 7 ml of coupling agent KH560 and 0.05 mol of acidic organic ligand 2,6-naphthalenedicarboxylic acid for 0.7 h, and obtain the sulfur-resistant ultra-low temperature manganese-based denitration catalyst after drying and low-temperature calcination at 500 °C for 3 h.

[0133] Steps (1), (2), and (3) are the same as those in Example 3.

[0134] Comparative Example 6

[0135] Compared with Example 3, the difference is only the type of acidic organic ligand added in step (4). The specific process is as follows:

[0136] (4) Immerse and load the matrix 2 prepared in step (3) in a 100 ml isopropanol solution containing 7 ml of coupling agent KH560 and 0.2 mol of acidic organic ligand 1,4-benzenedicarboxylic acid for 0.7 h, and obtain the sulfur-resistant ultra-low temperature manganese-based denitration catalyst after drying and low-temperature calcination at 500 °C for 3 h.

[0137] Steps (1), (2), and (3) are the same as those in Example 3.

[0138] Comparative Example 7

[0139] Compared with Example 4, the difference is only that strong acid etching is not carried out in step (3). The specific process is as follows:

[0140] (3) Calcinate the catalyst precursor prepared in step (2) at 400 °C for 4 h to obtain matrix 1;

[0141] (4) The matrix 2 prepared in step (3) was impregnated and loaded in a 100 ml formic acid solution containing 7 ml of coupling agent KH550 and 0.15 mol of acidic organic ligand 2,6-naphthalenedicarboxylic acid for 0.8 h, and after drying and low-temperature calcination at 400 °C for 4 h, an anti-sulfur ultra-low temperature manganese-based denitration catalyst was obtained.

[0142] Steps (1) and (2) are the same as those in Example 4.

[0143] Comparative Example 8

[0144] Compared with Example 4, the difference is only that the conditions of strong acid etching in step (3) do not meet the requirements. The specific process is as follows:

[0145] (3) The catalyst precursor prepared in step (2) was calcined at a low temperature of 400 °C for 4 h to obtain matrix 1. Matrix 1 was added to a sulfuric acid solution with a concentration of 2 mol / L at 20 °C and etched for 4 h, and after drying, matrix 2 was obtained;

[0146] (4) The matrix 2 prepared in step (3) was impregnated and loaded in a 100 ml formic acid solution containing 7 ml of coupling agent KH550 and 0.15 mol of acidic organic ligand 2,6-naphthalenedicarboxylic acid for 0.8 h, and after drying and low-temperature calcination at 400 °C for 4 h, an anti-sulfur ultra-low temperature manganese-based denitration catalyst was obtained.

[0147] Steps (1) and (2) are the same as those in Example 4.

[0148] Comparative Example 9

[0149] Compared with Example 4, the difference is only that the conditions of strong acid etching in step (3) are different. The specific process is as follows:

[0150] (3) The catalyst precursor prepared in step (2) was calcined at a low temperature of 400 °C for 4 h to obtain matrix 1. Matrix 1 was added to a hydrochloric acid solution with a concentration of 4 mol / L at 80 °C and etched for 4 h, and after drying, matrix 2 was obtained;

[0151] (4) The matrix 2 prepared in step (3) was impregnated and loaded in a 100 ml formic acid solution containing 7 ml of coupling agent KH550 and 0.15 mol of acidic organic ligand 2,6-naphthalenedicarboxylic acid for 0.8 h, and after drying and low-temperature calcination at 400 °C for 4 h, an anti-sulfur ultra-low temperature manganese-based denitration catalyst was obtained.

[0152] Steps (1) and (2) are the same as those in Example 4.

[0153] Comparative Example 10

[0154] Compared with Example 5, the difference is only that the calcination temperature in step (1) is too low. The specific process is as follows:

[0155] (1) In 1000 ml of deionized water, strontium source, zirconium source and ruthenium source additives (25.4 g of strontium nitrate, 18.64 g of zirconium chloride, and 0.17 g of ruthenium trichloride are added respectively, and the corresponding molar ratio is 12:8:0.08) are added to form an additive precursor solution. Subsequently, n-propanol, an organic solvent accounting for 40% by volume of the additive precursor solution, is added, and sulfonated polystyrene, a dispersant accounting for 2% of the mass of the corresponding oxides of the strontium source, zirconium source and ruthenium source additives, is added. After mixing evenly, ammonium carbonate, a precipitating agent, is added for precipitation reaction until the pH reaches 10. The temperature of the mixture is controlled at 70 °C, and ultrasonic treatment is carried out at a power of 240 W for 5 h while stirring to form a suspended additive precursor; the additive precursor is washed, filtered by suction, dried, and then calcined at a high temperature of 700 °C for 3 h, and ground at 300 r / min for 40 min to obtain the corresponding oxides of the catalyst additives;

[0156] Steps (2), (3), and (4) are the same as those in Example 5.

[0157] Test Example 1 Specific surface area and strength test

[0158] The pore volume and specific surface area of the sulfur-resistant ultra-low temperature manganese-based denitration catalysts prepared in Examples 1-7 and the manganese-based denitration catalysts prepared in Comparative Examples 1-10 were tested; catalyst strength performance test: According to the national standard of GB / T31587-2015 honeycomb flue gas denitration catalyst, a microcomputer-controlled electronic pressure testing machine (EM3-305) was used to test the axial and radial compressive strengths of the catalysts. The test results are shown in Table 1;

[0159] Table 1 Specific surface area and strength test

[0160]

[0161]

[0162] Test Example 2 Denitration and sulfur resistance test

[0163] The denitration and sulfur resistance related tests were carried out on the sulfur-resistant ultra-low temperature manganese-based denitration catalysts prepared in Examples 1-7 and the manganese-based denitration catalysts prepared in Comparative Examples 1-10, and the denitration rates and sulfur resistance effects are shown in Table 2;

[0164] Table 2 Denitration and sulfur resistance test

[0165]

[0166]

[0167] Result analysis

[0168] Through the analysis of Example 1, Comparative Example 1, and Comparative Example 2, it is confirmed that the addition of ruthenium and the timing of addition have certain effects on the pore volume, specific surface area, denitrification, and sulfur resistance of the final catalyst. In addition, considering Example 5 and Comparative Example 10, the calcination temperature of the promoter precursor in step (1) also affects the final catalyst effect. This may be because a higher calcination temperature of the promoter precursor is more conducive to the formation of solid solutions of promoters strontium, zirconium, and ruthenium, generating more oxygen vacancies and acidic sites, improving the specific surface area catalytic activity and acid resistance of the catalyst, and reducing the catalytic reaction temperature window.

[0169] Through the analysis of Example 2, Comparative Example 3, and Comparative Example 4, it is confirmed that the addition amounts of Mn and Fe and the molar ratio of Mn to Fe have certain effects on the pore volume, specific surface area, denitrification, and sulfur resistance of the final catalyst. Further, relatively speaking, when Mn is low and Fe is high (Comparative Example 3), since the strength of manganese oxide is higher than that of iron oxide, the overall catalyst strength is somewhat reduced, affecting the service life of the catalyst. When Mn is high and Fe is low (Comparative Example 4), the catalyst strength is high, but the strong acid etching effect is insufficient, the pore volume and specific surface area are reduced, and the low-temperature denitrification effect is reduced to a certain extent.

[0170] Through the analysis of Example 3, Comparative Example 5, and Comparative Example 6, it is confirmed that acidic organic ligands have little effect on the specific surface area and strength; however, the concentration and type of acidic organic ligands affect the denitrification efficiency. Since 2,6-naphthalenedicarboxylic acid has stronger acidity and hydrophobicity, it has a positive effect on the denitrification efficiency.

[0171] Through the analysis of Example 4, Comparative Example 7, Comparative Example 8, and Comparative Example 9, it is confirmed that whether etching is carried out, the temperature of acid etching, and the choice of acid for etching have great effects on the pore volume, specific surface area, and denitrification efficiency; Figure 1 and Figure 2 Figures 13 and 14 are SEM images of Example 4 at scales of 50 μm and 2 μm respectively, Figure 1 and the pit structure may be the effect of etching with sulfuric acid solution.

[0172] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity in description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered to be within the scope described in this specification. Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and deformations to the above embodiments within the scope of the present invention. In addition, without mutual contradiction, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples.

Claims

1. A preparation method of an anti-sulfur ultra-low temperature manganese-based denitration catalyst, characterized in that It includes the following steps: (1) Add a strontium source, a zirconium source, and a ruthenium source promoter to a solution to form a promoter precursor solution. Add an organic solvent and a dispersant, mix evenly, and then add a precipitant for precipitation reaction. After the reaction is completed, ultrasonic treatment, high-temperature calcination, and grinding are carried out to obtain the corresponding oxide of the catalyst promoter; (2) Disperse a manganese source, an iron source, the corresponding oxide of the catalyst promoter prepared in step (1), and a pore-forming agent in water, and obtain a catalyst precursor after intermittent ultrasonic treatment and aging; (3) The catalyst precursor obtained in step (2) is calcined at low temperature to obtain matrix 1, and matrix 1 is added to an acid solution containing SO4 2- for etching treatment, and after drying, matrix 2 is obtained; (4) Immerse and load the substrate 2 prepared in step (3) in a solution containing an acidic organic ligand, and obtain an anti-sulfur ultra-low temperature manganese-based denitrification catalyst after drying and low-temperature calcination.

2. The preparation method of the sulfur-resistant ultra-low temperature manganese-based denitration catalyst according to claim 1, characterized in that, The acidic solution containing SO4 2- in step (3) is sulfuric acid or sulfuric acid - copper sulfate.

3. The preparation method of the sulfur-resistant ultra-low temperature manganese-based denitration catalyst according to claim 1, characterized in that, In step (4), the acidic organic ligand is one or more of naphthalenedicarboxylic acid or pyrazoledicarboxylic acid, preferably 2,6-naphthalenedicarboxylic acid or 3,5-pyrazoledicarboxylic acid.

4. The preparation method of the sulfur-resistant ultra-low temperature manganese-based denitration catalyst according to claim 1, characterized in that, In terms of metal elements, the molar ratio of the manganese source, the iron source, the strontium source, the zirconium source, and the ruthenium source in the catalyst is 70∶(15~25)∶(2~15)∶(3~10)∶(0.01~0.1), preferably 70∶(18~22)∶(8~12)∶(6~8)∶(0.05~0.08).

5. The preparation method of the sulfur-resistant ultra-low temperature manganese-based denitration catalyst according to claim 1, characterized in that, The high-temperature calcination temperature in step (1) is 800~1200 °C, and the time is 3~8 h; and / or, the low-temperature calcination temperature in step (3) is 300~500 °C, and the time is 2~5 h; and / or, the low-temperature calcination temperature in step (4) is 300~500 °C, and the time is 2~5 h.

6. The preparation method of the sulfur-resistant ultra-low temperature manganese-based denitration catalyst according to claim 1, characterized in that, The strontium source in step (1) includes one or two of strontium chloride and strontium nitrate; and / or, the zirconium source in step (1) includes one or two of zirconium nitrate and zirconium chloride; and / or, the ruthenium source in step (1) includes one or two of ruthenium trichloride and ruthenium nitrate; and / or, the manganese source in step (2) includes at least one of manganese acetate, manganese nitrate, and manganese sulfate; and / or, the iron source in step (2) includes at least one of iron nitrate, iron sulfate, and iron chloride.

7. The preparation method of the sulfur-resistant ultra-low temperature manganese-based denitrification catalyst according to claim 1, characterized in that, The organic solvent in step (1) includes at least one of n-butanol, n-propanol, and glycerol; and / or, the dispersant in step (1) includes at least one of sulfonated polystyrene, sodium polyacrylate, and polyacrylamide; and / or, the precipitant in step (1) is an aqueous solution of an alkaline carbonate, preferably at least one of sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, ammonium carbonate, and ammonium bicarbonate; and / or, the pore-forming agent in step (2) is at least one of carboxymethyl cellulose, polyethylene oxide, polyethylene glycol, activated carbon, urea, starch, polyacrylamide, and polyvinyl alcohol; and / or, a coupling agent can be selectively added to the solution in step (4), preferably at least one of silane coupling agents KH540, KH550, and KH560.

8. The preparation method of the sulfur-resistant ultra-low temperature manganese-based denitration catalyst according to claim 1, characterized in that, The temperature of ultrasonic treatment in step (1) is 60~80 °C, the power is 40~240 W, and the time is 2~5 h; and / or, the grinding speed in step (1) is 300~500 r / min, and the time is 10~60 min; And / or, the power of the intermittent ultrasound in the step (2) is 50-100 W, and it stops for 15-25 min every 30-90 min of ultrasound, and the intermittent ultrasound is performed 3-5 times; And / or, the aging temperature in the step (2) is 15-30 °C, and the time is 5-10 h.

9. An anti-sulfur ultra-low temperature manganese-based denitration catalyst, characterized in that, Based on the metal element of the catalyst, the molar ratio of the manganese source, iron source, strontium source, zirconium source and ruthenium source is 70∶(15-25)∶(2-15)∶(3-10)∶(0.01-0.1), preferably 70∶(18-22)∶(8-12)∶(6-8)∶(0.05-0.08).

10. Application of a catalyst prepared by the preparation method of the sulfur-resistant ultra-low temperature manganese-based denitration catalyst according to any one of claims 1-8 or the sulfur-resistant ultra-low temperature manganese-based denitration catalyst according to claim 9 in NH3-SCR.

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